There has been a wireless electronics revolution in recent years due to the rapid advancements and adoption of many new digital wireless communication protocols. For example, Code Division Multiple Access (CDMA) and Global System for Mobile communication (GSM) have greatly increased the popularity of digital cellular telephones, Wi-Fi local area network (LAN) protocols, such as 802.11b, 802.11g, 802.11a, etc., have revolutionized wireless computer networks, and Bluetooth has provided a very useful short range wireless digital protocol for many different digital devices.
The advancement in wireless protocols has spawned a field of portable electronic devices that are capable of downloading, displaying, storing, and/or retrieving increasingly large amounts of data. Hence, modern mobile devices typically employ a variety of multimedia applications and data. Modern portable and/or mobile devices use system-on-a-chip or system on chip (SoC or SOC) technology, which advantageously integrates many components of a computer or other electronic system into a single integrated circuit, or IC chip. The single chip often contains digital, analog, mixed-signal, and often radio-frequency (RF) functions, and all on the one chip. Embedded systems often take advantage of system-on-chip technology. However, such systems conventionally have limited capabilities particularly in the areas of storage and/or bus bandwidth.
Meanwhile, multimedia applications can use significant amounts of bandwidth and storage resources. For instance, the transmission and/or display of digital video frames require memory, buffers, channels, and buses that can support a large volume of bits. Conventionally, image data is presented in frames comprising many pixels. Generally, higher resolution images use large numbers of pixels. Moreover, each pixel is represented by using a set of coefficients to describe the properties of the pixel such as the color, or luminance, or chrominance, for example. For color images, three coefficients of eight bits each are conventionally used for a single pixel. In a red-green-blue system (RGB), and variants thereof, 24 bits are used to represent each color, which is sometimes referred to as 24-bit pixel depth. Increasing the resolution, display size, or other qualities of a broadcast, further increases display frame size or other requirements. In particular, modern devices and broadcasts are capable of multimedia information that exceeds the traditional QVGA, VGA to XGA formats.
Higher data rate broadband transmission places even further demands on any system. For example, the bandwidth situation becomes worse when a LCD controller must support reading frame buffers at refresh rates approaching 100 Hz. Moreover, storage and/or retrieval of multimedia data that is used by the multimedia applications present similar problems. Previous attempts to address the issues described above have used compression techniques like run length encoding (RLE) and variants of run length encoding. However, these previous attempts suffer from a variety of drawbacks.